Bridge is the structure provide passage over on obstacle
without closing of the way. The passage may be a road , railway pedestrian etc

TYPES OF BRIDGES

1.timber bridges

2.Masontry bridges

3.Rcc bridges

4.Steel bridges

TIMBER BRIDGES

Timber bridges are classified as temporary bridges. These bridges
are very common and are suitable for hill, because they can be constructed with
local material and labour very quickly and economically, the cantilever and
suspension timber bridges are explained below.

TIMBER CANTILEVER BRIDGE

Timber cantilever bridges are suitable for light traffic the
construction of these bridges is very simple layers of timber logs are embedded
in the side banks. Another layer of timber logs projecting between 2 to 3 m
from the lower layer is laid on it.in this way layer over layers are laid with projections
from the bottom laters till 5 to 7 m gap is left in the middle. Road bearers
are laid over this gap and the bridge is completed by leveling the surface of
earth and stone ballast and the top is giver a smooth finish .

In hilly areas for crossing small valley of steam timber
suspension bridge. It consists of cables or ropes which bears the load of the roadway
through suspenders. The cables are secured anchored to the banks

MASONRY BRIDGE

The super structure of masonry bridges consists of masonry
arch over which the roadway is constructed .this arch rests on piers and abutments
.the arches may be semi circular semi elliptical parabolic and multi centered
types masonry arch bridges are suitable for small span bridges.

RCC BRIDGES

Rcc bridges are rigid ,durable ,economical and easy to
construct . The various types of rcc bridges are

1.slab bridges

2,rigid bridges

3.rcc arch bridges

SLAB BRIDGES

This is the simplest type of rcc bridge and easy to
construct .this consists of a slab of uniform thickness laid on two abutments .

TEE BEAM AND SLAB BRIDGES

This type of bridge consists of a concrete slab supported on
rectangular beam. Here the beams and slabs are cast monolithically and the supported
on abutments or piers ,these types of bridges are suitable for spans up to 20 m
.these bridges are commonly used for road bridges of canals and railway lines.

In this types of bridges the deck slab is made monolithic with
the abutments. The portal frame has stability has stability against lateral
forces such as wind and earthquake .these bridges are suitable for spans upto
20m.

RCC ARCH BRIDGES

These bridges are pleasing in appearance and can be economically
used upto span of about 200m. Some of the types of rcc arch bridges are
explained below.

FILLED SPANDREL ARCH BRIDGE

This consists of a desk slab supported by an arch rib. The
space between the arch and the deck slab is filled with earth .

OPEN SPANDREL RIBBED ARCH BRIDGES

In these type of bridges the deck slab is supported on the
columns which are in turn supported on arch rib.

BOW STRING GIRDER BRIDGE

This type of bridge consists of an arch rib from which the
deck slab is hung by mean of vertically members called suspenders. The
horizontal thrust is resisted by ties and the vertical reaction by suspenders
and the bow string girder because of the resemblance of the arch rib with above
and the tie beam with a string girder because of the resemblance of the arch
rib with above and the tie beam with a strong bow string arches are economical .when
sufficient headroom is required under a bridge . This types of bridges is
suitable for spans of 30m to 45m.

STEEL BRIDGES

Steel bridges are constructed to carry a highway railway
track for support of water pipes .oil pipes. These bridges are classified into
three types

1.Plate girder bridges

2.Steel truss bridges

3.Steel arch bridges

PLATE GIRDER BRIDGES

A plate girder is a built up beam
to carry heavier load over longer spans. Box girder have exceptional torsional
rigidity and better transverse load distribution .these bridges can be used for
urban highway structure like flyovers. Generally girder bridges are used for
simply supported spans less than 50m and for continuous span upto 26m.

STEEL TRUSS BRIDGES

Steel truss bridges are suitable
for long railway bridges or for combined road radio bridges they can be used
for spans up to 375m.

STEEL ARCH BRIDGES

These consists of trusses or
girders used in the form of curved beams called arch ribs. They may be fixed or
hinged steel arch bridges and are generally adopted for spans up to 250 m.

BOW STRING GIRDER TYPE BRIDGES

The string girder type bridge
derives its name from its shape .the arch rib and the tie respectively resemble
bow and string,. The flooring of bridges rests on ties and the load is
transmitted to the arch rib through suspenders. Suitable bracing may also be
provided in case of steel bow string girders.

CABLE STAYED BRIDGES

Cable stayed bridges may look similar to suspensions bridges both
have roadway that hang from cables and both have towers but the cables are
connected to the towers .in suspension bridges the cables ridge freely across
the towers transmitted the load to the anchorages at either end in cable stayed
bridges. The cable are attached to the lowers. Which alone bear the load. The cables
can be attached to the roadway in a variety of ways. In a radial pattern cables
extend from several points on the road to a
single point at the top of the tower in a parallel pattern cable are
attached at different height along the tower. Running parallel to one other.